Paradox Interactive has two of my favorite games, so when they had an RPG out, I gave it a shot. I had some Baldur's Gate type of vibes from this game once I started playing it. I started the Baldur's Gate games, but did not finish them.
Graphics - B- - It's your average RPG graphics. It gets the job done. It doesn't stick out or catch my eye.
Story and Atmosphere - A- - Not quite Ultima VII or Dragon's Age or DQIV level, but it is very good. There is some customization with backgrounds and you start off as someone off for a better life. Customization of attributes do matter. Some things you can't do without passing an attribute check. Events happen quickly and you become a Watcher that can read souls while at the same time are trying to figure out what happened to you. I won't spoil more than that. You travel to towns, recruit story companions on your team, hire companions if necessary (they aren't story members, just fighters you customize), and go on both sidequest and main quests. Fairly early into the game, you come across an old abandoned castle. If you do what needs to be done, that castle then becomes your HQ Suikoden style. Unlike Suikoden, you then upgrade the castle as needed to bring shops in, security, and prestige to get new missions. There's scripted parts that happen too. They often lead to injuries. If you are knocked out in battle or get dinged in a scripted event, you get an injury. Camping (you have up to 6 camping supplies at a time) or staying at an inn/castle heals injuries.
Length - A - With the expansions this game and the sidequests get to a good 70 hours or so. It starts to drag a little at the end, but generally kept my interest.
Difficulty A- - Adjustable. You can play on easy mode or almost impossible. Early in the game is more difficult with weak equipment and less people. It's a six person active party, and you will definitely need all spots filled when you go to the HQ abandoned castle or to Lord Raeric's castle. (11 total join, I think I had 4 join me before abandoned Castle HQ with one joining at the castle. I had a hired fighter as well in my party there) Once you start getting "exceptional" level equipment, more spells (fireball, neurotic lance, summoned creatures), more special attacks (knockdown) and "soulbound" equipment, things get easier although if you go places you shouldn't go early, you will learn real quickly. Side quests are more difficult than the main quest by and large. The castle basement levels post HQ are extremely tough the further you go (you're not supposed to finish the end parts until near the end of the game - take it part at a time). Some of the bounties are difficult at lower levels (the monks were my toughest fight). The mercs and the wizard sidequest is tough anytime with the wizard and his crew extremely tough boss. The eyeless quest in the expansion (toughest non-bosses in the game). As expected in RPGS, the toughest fight is not the final boss. It's the fight at the bottom of your castle and the fight in one cave in what was thought to be a routine sidequest. You don't have to fight them, however depending on the circumstances. You could talk your way out of one of those fights with the right attributes.
Combat and Play Control (PC) - B - Easy for me to work with for the most part. I prefer turned based to real time since I like to control everything, but for real time it's good. One 1/2 grade demerit goes to the absurdly low level cap of 16. That really pissed me off. One real nice feature however is that you can (for a cost) retrain your characters from level 1. That's nice when you need to change a character's role as someone enters the party.
Beginnings and Endings - B - The beginning is vague as is the midgame background. Eventually things start to make some sense at the end and tie the main quest and expansions together.
Bugs - B+ - I think I had one freeze and that's it.
Price - B - The game and both of the expansions/DLC were under $35.
Overall - B - It's a good game. I'm currently playing the sequel which I so far prefer to the original, but at the same time it makes the original better.
I highly recommend playing this game before playing Pillars of Eternity II. II is a true direct immediate sequel and it will spoil much of the first game, much more than Dragon Age games and even more than Mass Effect games (which also has some direct spoilers).